Since this project suffered the loss of Dr. L.M. Zucker, its long-standing Principal Investigator, a portion of the proposed work still involves the evaluation and liquidation of her unfinished studies of the "fatty" rat. The fatty rat appears to metabolize amino acids, notably lysine and glycine, in an abnormal manner. Such abnormalities may be related to the fatty's retarded musculo-skeletal growth. Hence, the influence upon growth and obesity of feeding and of restricting these two amino acids is to be investigated further. Because of the intimate association of lysine and glycine with connective tissue, the status of connective tissue of the fatty is to be evaluated through quantitative determinations of total carcass hydroxy-lysine and hydroxy-proline. A qualitative study of the fatty's morphological response to chronic irritation is also envisaged.